1. Field of the Invention
The present invention relates to a portable terminal having a plurality of display units, such as portable telephone, and more particularly, to a luminance control technique of each display unit.
2. Description of the Related Art
JP 2008-236144 describes a technique of reducing power consumption of a portable terminal such as portable telephone so as to prolong battery life.
According to the technique of JP 2008-236144, at a state where a backlight which is provided to an operation unit so as to improve visibility of keys is turned on, brightness of the backlight is reduced when any input is not made to the operation unit for a predetermined time or longer.
In recent years, a portable terminal having a plurality of display units has been proposed. In order to reduce the power consumption, it is conceivable that the technique of JP 2008-236144 were also applied to the portable terminal to reduce display luminance of each display unit when there is no user operation made for a predetermined time period.
However, even if the technique of JP 2008-236144 were applied to the portable terminal having a plurality of display units, it would be not possible to reduce the power consumption while the user is operating the portable terminal.